In the production of sheet material, such as bed sheets, curtains, bed spreads, etc., the goods usually are cut from a supply of sheet material and the cut edges are hemmed. In some situations the side edges of the cut segments of sheet material do not need to be hemmed since the side edges comprise a selvage of the sheet material. Thus, only the cut edges need to be folded and sewn into a hem.
Various automatic machines have been developed and used for cutting and hemming sheet material. For example, U.S. Pat. Nos. 3,580,198, 3,640,235, 3,772,948, 3,906,878 and 3,955,515 all illustrate systems which appear to be capable of automatically cutting segments from sheet material and hemming the cut edges of the segments. However, it is understood that the prior art devices have experienced some difficulty in controlling the cut edges of the segments of sheet material as the cut edges are being moved to and through a hemmer. This difficulty is increased when a large hem is to be formed at the cut edge of the segment of sheet material. For example, the large hem at the head of a bed sheet usually is visible when in use by the purchaser, and it is desirable to have this hem formed with a constant width, so that it is uniform and attractive to the purchaser. However, when the hem at the head of a bed sheet is formed with automatic hem forming equipment, it is difficult to control the wide expanse of folded material so as to accurately and rapidly form the hem.